Question

Cuvette 1

volume of PBS (microL) = 965

Volume of B-lactamase (microL)= 10

Volume of Nitrocefin (microL)= 25

what is the final concentration of Nitrocefin in microM?

Please show work and explain. Thanks

Answer 1

volume of PBS (microL) = 965*10^-6 L

Volume of B-lactamase (microL)= 10 * 10^-6 L

Volume of Nitrocefin (microL)= 25*10^-6 L

total volume of this mixture in cuvate = (965*10^-6 L + 10 * 10^-6 L + 25*10^-6 L) = 1.0 * 10^-3 L

If concentration of Nitrocefin in stock solution = x microM.

so using dilution law,

V1*S1 (before mixing) = V2 * S2 (after mixing)

25*10^-6 L * x microM. =   1.0 * 10^-3 L * S2

S2 = 25*10^-3*x microM

S2 = 0.025 * x microM

so final concentration of Nitrocefin in microM = 0.025 * x